The present invention relates to retaining frames for removably securing a sheet of glazing material adjacent other sheets of glazing material. More particularly, the present invention pertains to a construction for removably retaining a sheet of light transmissive insulating glazing adjacent framed skylight glazing or the like.
More than one layer of glazing material is often employed in planar and domed skylight construction. Both the exterior glazing layer and the interior glazing layer may be comprised of, for example, glass, acrylic, or polycarbonate. The choice of glazing material employed depends upon optimizing such factors as U-value, heat gain, and shading co-efficient.
Increasingly stringent building energy codes have caused homebuilders and owners to be more aware of insulating properties of the glass installed in homes. Specifically, glazing materials and layers of glazing materials having specific minimum U-values (BTU/hours.times.square feet.times..degree.F.) are often required to meet code specifications. A particular problem in the glass industry is satisfying the code specifications without losing light transmission through the glazing layers. In skylight construction, the interior glazing layers are often comprised of light transmissive insulating materials such as, for example, polycarbonate resin. These light transmissive insulating materials are frequently employed to attain satisfactory U-values. However, the glazing industry is currently lacking an adequate construction for removably securing these light transmissive insulating glazing materials adjacent to traditional skylight glazing.
Regardless of the glazing materials employed as the exterior and interior glazing layers, when multiple layers are used cleaning of the inside surface of the interior glazing layer is currently difficult. The retaining frames presently employed include complex components that are necessary to ensure a safe, secure connection of the two glazing layers. The complexity of these connections causes cleaning of the glazing and other skylight maintenance to be unduly labor intensive.
Specifically, a need exists for a lightweight yet strong construction for removably securing either insulating or non-insulating glazing to traditional skylight glazing, this construction being manufactured from economical materials. A need also exists for a construction of the above type that is convenient to connect and to separate, but that does not separate readily when foreign objects such as rocks, tree branches or hail break through the fragile skylight glazing and impact upon the shatter resistant insulating glazing.